Neuregulin signaling pathway in smoking behavior

Area of Science:

• Neuroscience
• Genetics
• Pharmacology

Background:

• Comorbidities between addictions and mental disorders, like schizophrenia and smoking, suggest shared molecular pathways.
• The Neuregulin signaling pathway (NSP) is implicated in schizophrenia, and its components, such as ERBB4, have shown associations with nicotine dependence.
• Neuregulin3 has demonstrated a link to nicotine withdrawal in mouse models, further supporting NSP's role in addiction.

Purpose of the Study:

• To investigate the association and linkage between genetic variants in 10 NSP genes and phenotypes related to smoking and alcohol use.
• To identify specific genetic variants within the NSP that contribute to smoking initiation, nicotine dependence, and nicotine withdrawal.
• To explore the functional implications of associated variants through expression and methylation quantitative trait loci (eQTL and meQTL) analyses.

Main Methods:

• Utilized a Finnish twin family sample (N=1998 from 740 families) to analyze 15,036 common, low frequency, and rare genetic variants across 10 NSP genes.
• Conducted association and linkage analyses to identify variants linked to smoking initiation, nicotine dependence, and nicotine withdrawal.
• Performed comprehensive annotation of associated variants using eQTL and meQTL analyses in a Finnish population, with in silico replication in public databases and brain tissue.

Main Results:

• Identified 66 genetic variants (in 23 LD blocks) significantly associated with smoking initiation, nicotine dependence, and nicotine withdrawal (FDR P<0.05).
• Annotated 25 eQTLs in NRG1 and ERBB4, and 22 meQTLs in NRG3, ERBB4, and PSENEN.
• Discovered a missense variant in NRG1 (rs113317778) and a splicing disruption variant in ERBB4 (rs13385826).
• Replicated a majority of blood-based QTLs in silico, with additional QTLs identified in brain tissue.

Conclusions:

• The Neuregulin signaling pathway (NSP) plays a significant role in smoking behavior.
• No significant association was found between NSP variants and alcohol use or abuse.
• Functional potential was identified for 56 of the 66 associated single-nucleotide polymorphisms, suggesting specific molecular mechanisms underlying smoking behavior.